John Ratzenberger Reunites with Cheers Cast Members

The actress, 64, lost 50 lbs. with Jenny Craig and has kept off the weight for the past year – and now she’s celebrating her success with some familiar faces in a Cheers-themed commercial for the diet program.

“When they asked me to do the commercial, I had a lot of consideration that it was an iconic show – I didn’t want to walk onto some set that looks artificial,” Alley tells PEOPLE.

But her fears were put to rest when she saw the set, which perfectly recreated the bar from the popular 80s sitcom.

“Honestly, when John [Ratzenberger] and George [ Wendt] and I walked on, it was a little bit like The Twilight Zone because it was an exact duplicate,” she says. “It was crazy. I didn’t think anybody would ever be able to replicate that set like that.”